TWI752017B - Films and electrical insulating sheets, adhesive tapes, and rotary machines using the same - Google Patents

Abstract

A thin film excellent in electrical insulation, heat dissipation and processability is provided. Furthermore, by using this film, an electrical insulating sheet excellent in thermal conductivity, a rotary machine using the electrical insulating sheet, an adhesive tape, and the like are provided. It is a thin film in which the number SPc (4000) of coarse protrusions on at least one surface is 15 pieces/mm ^{2 or more.}

Description

Films and electrical insulating sheets, adhesive tapes, and rotary machines using the same

The present invention relates to a film. Furthermore, the present invention relates to an electrical insulating sheet and an adhesive tape using the film.

Polyester (especially polyethylene terephthalate (hereinafter referred to as PET) or polyethylene 2,6-naphthalate, etc.) resin and polyarylene sulfide (especially polyphenylene sulfide (hereinafter referred to as PPS) ) etc.) resins are excellent in mechanical properties, thermal properties, chemical resistance, electrical properties and moldability, and can be used in various applications. Due to the excellent mechanical properties and electrical properties of polyester films and polyarylene sulfide films made of these resins, they are used in copper-clad laminates, back sheets for solar cells, adhesive tapes, flexible printed circuit boards, Membrane switches, planar heating elements, flat cables, insulating materials for rotating machines, electrical insulating materials for batteries, etc., magnetic recording materials, materials for capacitors, packaging materials, automotive materials, building materials, photographic applications, image applications , heat transfer and other uses.

Among these applications, among insulating materials for rotating machines (eg, insulating materials for generators, insulating materials for vehicle motors, and insulating materials for general industrial motors), in recent years, due to the miniaturization and high output of rotating machines, the area around coils Heat generation and heat storage have occurred, so the temperature rise in the system will cause a reduction in the output of the rotating machine, an increase in power consumption, and a reduction in the life of the material. problem. Similarly, even in solar cell backsheet materials, reflector materials, LED substrate materials, circuit materials, and lithium-ion battery materials, the temperature rise in the system has become remarkable due to recent high output and miniaturization.

Therefore, it is important to conduct/dissipate the heat generated inside and manage the heat outside, and thus a film with high heat dissipation is required. Various materials of films with high heat dissipation have been proposed so far, for example, a composite film in which a protective layer of PET film is laminated on one side or both surface layers of a graphite sheet with high thermal conductivity (Patent Document 1), A film containing a fibrous carbon material in a biaxially stretched PET film (Patent Document 2, Patent Document 3) or the like.

[Prior Art Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2008-80672

Patent Document 2: Japanese Patent Application Laid-Open No. 2013-28753

Patent Document 3: Japanese Patent Laid-Open No. 2013-38179

However, in the technique of Patent Document 1, in addition to the problems that the graphite sheet is fragile and the workability is poor, the thermal conductivity of the PET film serving as the protective layer is low, and the high heat dissipation property of the graphite sheet cannot be fully exerted. Moreover, in the technique of patent document 2 and patent document 3, since a thin film has electroconductivity, it cannot be used for the application which requires insulation. In addition, when the film material is used as a heat dissipation material, the adhesion to the interface of the place to be dissipated can be improved. , It is important to reduce the thermal resistance of the interface, and in order to improve the interface adhesion, it may be assembled in the machine through the so-called interface filler such as adhesive, varnish, grease, and adhesive. However, the thin films of Patent Documents 1 to 3 have a smooth surface, so that the contact surface area between the interface filler and the thin film is reduced, and as a result, the thermal resistance at the interface increases, and sufficient heat dissipation may not be exhibited.

Therefore, an object of the present invention is to provide a thin film excellent in electrical insulating properties, heat dissipation properties, and processability.

In order to solve the above-mentioned problems, the present invention is constituted as follows.

(1) A thin film in which the number of coarse projections SPc (4000) on at least one surface is 15 pieces/mm ² or more.

(2) The thin film according to (1), wherein the thin film has a layer (P1 layer) containing inorganic particles, when the content of the inorganic particles in the P1 layer is Vf1 (volume %), and the porosity in the P1 layer is set as In the case of Va (volume %), Va/Vf1 is 1 or less.

(3) (2) film according to of which in cross-section in a manner perpendicular to the film plane direction and parallel to the film longitudinal direction of cut of the P1 layer, when ² Number of the inorganic particles per 10000μm existence of Nf of (a), Nf/Vf1 is 25 or less.

(4) The thin film according to (2) or (3), wherein the average equivalent circle diameter of the inorganic particles is 3 μm or more in a cross section of the P1 layer taken perpendicular to the thin film surface direction and parallel to the thin film longitudinal direction.

(5) The thin film according to any one of (1) to (4), wherein the thin film has a layer (P1 layer) containing inorganic particles, the thickness of the thin film is set to T (μm), and the number of coarse protrusions SPc (4000 ) is 15/mm ² or more, when the inorganic particle content in the range from the surface to the thickness 0.1T is Vfa (volume %), and the range from the thickness 0.1T to the thickness 0.9T When the content of the inorganic particles is Vfb (volume %), Vfa/Vfb satisfies 0≦Vfa/Vfb<1.

(6) The thin film according to any one of (1) to (5), wherein the thermal conductivity in the thickness direction of the thin film is 0.15 W/mK or more, and the surface specific resistance is 10 ¹³ Ω/□ or more.

(7) The film according to any one of (1) to (6), wherein the film is mainly composed of a polyester resin.

(8) The thin film according to any one of (1) to (7), wherein the ^{surface roughness Ra of the surface where the number of coarse protrusions SPc(4000) is 15 pieces/mm 2} or more is 100 nm or more.

(9) An electrical insulating sheet using the thin film according to any one of (1) to (8).

(10) An adhesive tape obtained by using the film according to any one of (1) to (8).

(11) A rotating machine using the electrical insulating sheet described in (9).

According to the present invention, it is possible to provide a film which is superior in electrical insulation, heat dissipation and processability than conventional films, and the film can be suitably used in copper clad laminates, back sheets for solar cells, adhesive tapes, flexible printing Circuit boards, membrane switches, planar heating elements, flat cables, insulating materials for rotating machines, insulating materials for batteries, etc., where electrical insulation and heat dissipation are important. In addition, it can also be used in adhesive tapes, release films, transfer films, design sheets, building materials, etc. by taking advantage of the surface properties of the film.

1‧‧‧Length (l)

2‧‧‧Width (b)

3‧‧‧Thickness (t)

4‧‧‧Protrusion of the mold

5‧‧‧Concave part of mold

X‧‧‧Pitch of die protrusions

Y‧‧‧Width of die protrusion

Z‧‧‧The height of the die protrusion

[ Fig. 1] Fig. 1 is a diagram schematically showing an example of a particle surrounded by a circumscribed rectangular parallelepiped.

[ Fig. 2 ] A diagram schematically showing an example of a mold shape.

[Form of implementing the invention]

In the film of the present invention, SPc(4000) on at least one surface of the film must be 15 pieces/mm ² or more. SPc is an index representing surface roughness. In the present invention, SPc(4000) is determined by the measurement method described later, and represents the number of protrusions of 4000 nm or more per reference area. When SPc(4000) is 15 pieces/mm ² or more, it means that there are a certain number or more of large protrusions on the film surface. The SPc (4000) of the surface of at least one side is within the above-mentioned range, thereby increasing the surface area of the interface and effectively dissipating heat. More preferably, it is 30 pieces/mm ² or more, and still more preferably 50 pieces/mm ² or more. When the SPc (4000) is less than 15 pieces/mm ² , the contact area between the film and the interface filler becomes smaller, and the heat transfer at the interface may be limited. The upper limit of SPc(4000) is not particularly limited, but in order to prevent the interfacial filler from being hindered due to the excessively small protrusion interval, it is preferably 1000 pieces/mm ² or less, more preferably 800 pieces/mm ² or less.

The method for setting the SPc(4000) on the surface of the film within the above-mentioned range is not particularly limited, but for example, a method of making the film contain inorganic particles, a method of using a mold with fine concavo-convex shapes so that the SPc(4000) is within the above-mentioned range can be mentioned. A method of processing the film surface, etc. In addition, in the method of making the thin film contain inorganic particles, in order to make the thin film surface When SPc (4000) is set in the above range, it is necessary to contain particles with a high concentration and large particle size. However, when the SPc (4000) on the surface of the thin film is set in the above range by the method of containing inorganic particles in the thin film, the type of inorganic particles It is preferable to control the surface activity and content, or control the elongation conditions to suppress particle slippage or interfacial exfoliation at the interface of inorganic particles.

In the present invention, the resin that becomes the main component of the film is not particularly limited, and preferred examples include: (i) polyethylene terephthalate, polyethylene 2,6-naphthalate, polyethylene terephthalate, and polyethylene terephthalate. Polyester resins of propylene phthalate, polybutylene terephthalate, etc.; (ii) Biodegradable resins of aliphatic polyester resins, aliphatic aromatic polyesters, polysaccharides, polymers containing starch, etc. ; (iii) acrylic resins such as poly(meth)acrylates; (iv) polyethylene, polypropylene, polymethylpentene, polyisoprene, epoxy-modified polyolefin, acid-modified polyolefin , alicyclic polyolefin resin and other polyolefin resins; (v) polyamide resin, polycarbonate, polystyrene, polyether, polyesteramide, polyetherester, polyvinyl chloride, polyvinyl alcohol , polyacetal, polyarylene sulfide, polyether ether ketone, polyurethane, polyamide, polyaryloxide, polyimide, polyetherimide, polyester elastomer, polyamide elastomer , other resins such as polyolefin elastomers; (vi) hardening resins such as epoxy resins, unsaturated polyester resins and other hardening resins, and copolymers or mixtures of these as components. Among them, polyester resins and polyarylene sulfide resins which are excellent in film-forming properties, heat resistance and dimensional stability are particularly suitable, and polyester resins which are excellent in film-forming properties and processability are more preferably used. In addition, in this invention, when expressing "main component", it shows that the ratio of this component in all components is 50 volume% or more, Preferably it is 60 volume% or more.

In the present invention, polyester refers to a resin comprising a dicarboxylic acid constituent and a dihydric alcohol constituent as main constituents. The polyester used in the present invention is based on JIS K-7122 (1987), and the resin is heated at a temperature increase rate of 20°C/min from 25°C (first run) to 300°C at a temperature increase rate of 20°C/min. , after maintaining in this state for 5 minutes, then quenching so that it becomes below 25°C, and then increasing the temperature from 25°C to 300°C at a temperature increase rate of 20°C/min. Differential scanning calorimetry of the second operation Among them, a resin whose crystal fusion heat ΔHm obtained from the peak area of the melting peak is 15 J/g or more is preferable. The crystal fusion heat ΔHm is more preferably 20 J/g or more, particularly preferably 25 J/g or more, and particularly preferably 30 J/g or more. By using such a polyester, in the production method described later, alignment and crystallization are easy, and a film with high heat resistance can be produced. In addition, in this specification, when a structural component is a polyester, the minimum unit which can be obtained by hydrolysis is shown. Furthermore, in this specification, when expressing "main constituent", the ratio of the constituent to all constituents is 80 mol % or more, preferably 90 mol % or more, more preferably 95 mol % above.

The above-mentioned dicarboxylic acid constituting the polyester includes, for example, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, dimer acid , Aliphatic dicarboxylic acids such as eicosanedioic acid, pimelic acid, azelaic acid, methylmalonic acid, ethylmalonic acid, etc.; adamantane dicarboxylic acid, norbornene dicarboxylic acid, isosorbide , cyclohexanedicarboxylic acid, decahydronaphthalene dicarboxylic acid and other alicyclic dicarboxylic acids; terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid Acid, 2,6-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 5-sodium sulfonic acid isophthalic acid, anthracene dicarboxylic acid, phenanthrene dicarboxylic acid, 9,9'- Aromatic dicarboxylic acids such as bis(4-carboxyphenyl)fornic acid, or ester derivatives thereof, are not limited to these. In addition, oxyacids such as l-lactide, d-lactide, hydroxybenzoic acid, and derivatives thereof, and oxyacids in consecutive plurals, etc., can also be used at the carboxyl terminus of the above-mentioned various carboxylic acid constituents. Achievers. In addition, these systems may be used alone, or a plurality of types may be used as required.

In addition, the above-mentioned diol constituents constituting the polyester include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, Alicyclic diols such as 1,3-butanediol; alicyclic diols such as cyclohexanedimethanol, spiroglycerol, isosorbide, etc.; bisphenol A, 1,3-benzenedimethanol, Examples of diols such as 1,4-benzenedimethanol, 9,9'-bis(4-hydroxyphenyl) fluoride, aromatic diols, and a plurality of the above-mentioned diols in succession, etc., are not limited to such. In addition, these systems may be used alone, or a plurality of types may be used as required.

Furthermore, in the film of the present invention, when the main component is a polyester resin, the ratio of the aromatic dicarboxylic acid constituent in all the dicarboxylic acid constituents is preferably 90 mol % or more and 100 mol % or less. More preferably, it is 95 mol% or more and 100 mol% or less. Still more preferably 98 mol % or more and 100 mol % or less, particularly preferably 99 mol % or more and 100 mol % or less, and most preferably 100 mol %, that is, all the components of the dicarboxylic acid can be aromatic. carboxylic acid constituents. If it is less than 90 mol%, the heat resistance may decrease. When the ratio of the aromatic dicarboxylic acid constituent among all the dicarboxylic acid constituents is 90 mol % or more and 100 mol % or less, alignment and crystallization are likely to occur in the production method described later, and a film with high heat resistance can be produced. .

In the film of the present invention, when the main component is polyester resin, the As the repeating unit system composed of the dicarboxylic acid constituent and the diol constituent, ethylene terephthalate, ethylene-2,6-naphthalene dicarboxylate, propylene terephthalate, terephthalic acid can be suitably used. Those composed of butanediester, 1,4-cyclohexene dimethylene terephthalate, and ethylene-2,6-naphthalenedicarboxylate are preferred as the main repeating unit. In addition, the main repeating unit referred to here refers to a repeating unit in which the total of the repeating units is 80 mol% or more, preferably 90 mol% or more, and more preferably 95 mol% or more of all repeating units. Furthermore, from the viewpoints of cost, ease of polymerization, and heat resistance, those having ethylene terephthalate and ethylene-2,6-naphthalene dicarboxylate as main repeating units are preferred. In this case, when ethylene terephthalate is used as the main repeating unit, a film with heat resistance that is cheaper and versatile can be obtained, and ethylene-2,6-naphthalene dicarboxylate is used as the main repeating unit When used, it can be made into a film with better heat resistance.

A polyester can be obtained by appropriately combining and polycondensing the above constituents (dicarboxylic acid and diol), but a constituent having three or more carboxyl groups and/or hydroxyl groups or the like is also preferred. In this case, it is preferable that the copolymerization ratio of the constituents having 3 or more carboxyl groups and/or hydroxyl groups is 0.005 mol% or more and 2.5 mol% or less with respect to all the constituent components of the polyester, since the stretchability of the film can be improved.

In the film of the present invention, when the main component is a polyester resin, the intrinsic viscosity (hereinafter; IV) of the polyester is preferably 0.6 or more. More preferably, it is 0.65 or more, still more preferably 0.68 or more, and particularly preferably 0.7 or more. When the IV is small, and when inorganic particles described below are contained, the entanglement between molecules becomes too small, and mechanical properties cannot be obtained, or mechanical properties over time tend to deteriorate, or brittleness tends to occur. In the film of the present invention, by setting the IV of the polyester to be 0.6 or more , high mechanical properties and high durability can be obtained. In addition, the upper limit of IV is not particularly determined, but there is a case where cost is disadvantageous due to an increase in polymerization time, or melt extrusion becomes difficult. Therefore, 1.0 or less is preferable, and 0.9 or less is more preferable.

Furthermore, in order to obtain the polyester of the above-mentioned IV, there are methods of discharging, bundling, cutting, and pelletizing by melt polymerization at a point when the melt viscosity reaches a predetermined melt viscosity, and a method of obtaining an inherent viscosity lower than the target. A method obtained by temporarily forming small pieces and then performing solid-phase polymerization. Among them, in particular, when the IV is 0.65 or more, thermal degradation can be suppressed and the number of carboxyl terminal groups can be reduced. It is obtained by temporarily forming small pieces with an intrinsic viscosity lower than the target, and then performing solid-phase polymerization. method is better. Furthermore, in the method described later, solid-phase polymerization is performed when the polyester contains inorganic particles, since the IV of the film can be further improved. As a result, when an inorganic particle is contained in polyester and a film is formed in the production method described later, excessive crystallization can be suppressed, so that the stretchability can be improved, and the mechanical properties of the obtained film can be improved.

In the film of the present invention, when the main component is a polyester resin, the melting point Tm of the polyester is preferably 240°C or higher and 290°C or lower. The melting point Tm mentioned here is the melting point Tm in the heating process (heating rate: 20°C/min) obtained by DSC, by the method according to JIS K-7121 (1987), at a temperature increase rate of 20°C/min Heating from 25°C (1st operation) to 300°C, maintaining this state for 5 minutes, then quenching so as to be 25°C or lower, and heating from 25°C to 300°C at a temperature increase rate of 20°C/min. The temperature at the top of the crystal melting peak of the two runs was taken as the melting point Tm of the polyester. The melting point Tm is more preferably 245°C or higher and 275°C or lower, and more preferably Above 250°C and below 265°C. When the melting point Tm is less than 240°C, the heat resistance of the film may be inferior, which is undesirable, and when the melting point Tm exceeds 290°C, extrusion processing may become difficult, which is undesirable.

唑啉基、環氧基、碳二亞胺基、異氰酸酯基等之取代基的化合物等。在使用耐水解劑時，相對於聚酯總量，較佳為含有0.01質量%以上。更佳為0.1質量%以上。藉由組合上述聚酯並添加耐水解劑，可抑制因無機粒子添加所致之聚酯之劣化，可進一步提高機械特性、耐熱性。而且， 從過剩之耐水解劑會降低阻燃性情形之觀點來看，耐水解劑之含量上限較佳為2質量%以下，更佳為1質量%以下，進一步較佳為0.8質量%以下。 In the film of the present invention, when the main component is a polyester resin, the number of carboxyl end groups of the polyester is preferably 40 equivalents/t or less. More preferably, it is 30 equivalents/t or less, and still more preferably 20 equivalents/t or less. When the number of carboxyl terminal groups is high, even if the structure is controlled, hydrolysis or thermal decomposition may be promoted due to the strong catalytic action of protons derived from the carboxyl terminal groups, and the deterioration of the film may be more likely to proceed. By making the number of carboxyl terminal groups into the above-mentioned range, it is possible to obtain a thin film that suppresses deterioration such as hydrolysis or thermal decomposition. In addition, in order to make the number of carboxyl terminal groups to be 40 equivalents/t or less, it can be obtained by using a polyester obtained as follows: 1) The dicarboxylic acid constituent and the diol constituent are subjected to an esterification reaction, and then by melt polymerization When the melt viscosity reaches a predetermined point, it is discharged, bundled, and cut, and after small pieces, it is a method of solid-phase polymerization; During the period of less than 0.3), the method of adding a buffer, a combination of the like, etc. Furthermore, it can also be obtained by adding a buffer or an end-capping agent at the time of molding. The terminal-capping agent means a compound that reacts and bonds with a carboxyl terminal group or a hydroxyl terminal group of the polyester, so that the catalytic activity of the proton derived from the terminal group disappears. Specifically, there are exemplified:

Substituent compounds of oxazoline group, epoxy group, carbodiimide group, isocyanate group, etc., etc. When using a hydrolysis-resistant agent, it is preferable to contain 0.01 mass % or more with respect to the total amount of polyester. More preferably, it is 0.1 mass % or more. By combining the above-mentioned polyester and adding a hydrolysis-resistant agent, the deterioration of the polyester due to the addition of inorganic particles can be suppressed, and the mechanical properties and heat resistance can be further improved. Furthermore, the upper limit of the content of the hydrolysis resistance agent is preferably 2 mass % or less, more preferably 1 mass % or less, and still more preferably 0.8 mass % or less, from the viewpoint that the excessive hydrolysis resistance agent reduces the flame retardancy.

When the thin film of the present invention has a layer (P1 layer) containing inorganic particles, and the inorganic particle content in the P1 layer is Vf1 (volume %), and the porosity in the P1 layer is Va (volume %), Va/ Vf1 series is preferably less than 1. The so-called inorganic particle content Vf1 (volume %) is obtained by the measurement method described later, and in the cross-sectional SEM image of the cross-section of the P1 layer taken perpendicular to the film surface direction and parallel to the film longitudinal direction, The area ratio of the inorganic particles occupied in the cross-sectional area of the thin film was obtained. In addition, the porosity Va (volume %) referred to here is obtained by the measurement method described later, in the cross-sectional SEM image of the cross-section of the P1 layer taken perpendicular to the film surface direction and parallel to the film longitudinal direction. , the ratio of the area of the void occupied in the cross-sectional area of the film, to obtain the ratio. Va/Vf1 is more preferably 0.8 or less, and still more preferably 0.6 or less. When Va/Vf1 exceeds 1, the air with low thermal conductivity in the film is mostly, and as a result, the heat dissipation property of the film is lowered. The lower limit of Va/Vf1 is 0. In the thin film of the present invention, high heat dissipation can be obtained by setting Va/Vf1 to be 1 or less.

唑啉基、環氧基、碳二亞胺基、異氰酸酯基、酸酐基等之取代基。尤其是，當從與聚酯之反應性高，且形成之 鍵結的耐熱性高之觀點來看，特佳為環氧基。尤其是，在無機粒子之表面具有反應性取代基時，在聚酯與無機粒子之混練時形成鍵結，因而形成強固的界面，故在後述延伸步驟中，可抑制聚酯與無機粒子界面之界面剝離。 In the film of the present invention, when the main component is a polyester resin, since Va/Vf1 is 1 or less, one containing a substituent reactive with polyester (hereinafter referred to as a reactive substituent) is used on the surface of the inorganic particles. better. The so-called reactive substituent here is a substituent which can react with a carboxyl terminal group or a hydroxyl terminal group of the polyester to be bonded, and specifically, it can be exemplified:

Substituents of oxazoline group, epoxy group, carbodiimide group, isocyanate group, acid anhydride group, etc. In particular, an epoxy group is particularly preferred from the viewpoint of high reactivity with polyester and high heat resistance of the formed bond. In particular, when the surfaces of the inorganic particles have reactive substituents, bonds are formed during the kneading of the polyester and the inorganic particles, thereby forming a strong interface. Therefore, in the extension step described later, the interface between the polyester and the inorganic particles can be suppressed. Interface peeling.

In the thin film of the present invention, the amount of the reactive substituent per unit surface area of the inorganic particles is preferably 0.2×10 ^-6 mol/m ² or more and 1.4×10 ^-4 mol/m ² or less. More preferably, it is 1 × 10 ^-5 mol/m ² or more × 10 ^-4 mol/m ² or less, and still more preferably 1.3 × 10 ^-5 mol/m ² or more and 5 × 10 ^-5 mol/m ² or less. Below 0.2 × 10 ^-6 mol/m ² , the bonding between the polyester and the inorganic particles becomes insufficient, causing significant interfacial peeling during elongation, resulting in a decrease in thermal conductivity. Furthermore, when it exceeds 1.4×10 ^-4 mol/m ² , the amount of bonding becomes too large and the elongation decreases. In the thin film of the present invention, since the amount of the reactive substituent per unit surface area of the inorganic particles is 0.2×10 ^-6 mol/m ² or more and 1.4×10 ^-4 mol/m ² or less, it is possible to have both thermal conductivity and thermal conductivity. Extensibility.

唑啉基、環氧基、碳二亞胺基、酸酐基、異氰酸酯基等之矽烷偶合劑、鈦偶合劑、鋁酸鹽系偶合劑，該等之中，宜使用2-(3,4-環氧基環己基)乙基三甲氧基矽烷、3-環氧丙氧基丙基甲基二甲氧基矽烷、3-環氧丙氧基丙基三甲氧基矽烷、3-環氧丙氧基丙基甲基二乙氧基矽烷、3-環氧丙氧基丙基三乙氧基矽烷、環氧丙氧基辛基三甲氧基矽烷等之具有環氧基的矽烷偶合劑；3-異氰酸酯丙基三乙氧基矽烷、3-異氰酸酯丙基三甲氧基矽烷等之具有異氰酸酯基的矽烷偶合劑； 3-三甲氧基矽基丙基琥珀酸酐等之具有酸酐基的矽烷偶合劑等。而且，亦宜使用具有反應性取代基之烷氧基寡聚物等。而且，亦宜使用甲基丙烯酸環氧丙酯等之具有環氧基的單體、2-異氰酸酯乙基甲基丙烯酸酯等之具有異氰酸酯基的單體與苯乙烯、乙烯、丙烯、丙烯酸等共聚之樹脂；聚碳二亞胺、含

唑啉基之樹脂等。該等之中，本發明之薄膜的主成分為聚酯樹脂時，從可在聚酯與無機粒子之兩者形成鍵結而形成強固的界面之觀點上，特佳為：2-(3,4-環氧基環己基)乙基三甲氧基矽烷、3-環氧丙氧基丙基甲基二甲氧基矽烷、3-環氧丙氧基丙基三甲氧基矽烷、3-環氧丙氧基丙基甲基二乙氧基矽烷、3-環氧丙氧基丙基三乙氧基矽烷、環氧丙氧基辛基三甲氧基矽烷等之具有環氧基的矽烷偶合劑；3-異氰酸酯丙基三乙氧基矽烷、3-異氰酸酯丙基三甲氧基矽烷等之具有異氰酸酯基的矽烷偶合劑；3-三甲氧基矽基丙基琥珀酸酐等之具有酸酐基的矽烷偶合劑；具有反應性取代基之烷氧基寡聚物。而且，亦較宜使用上述之具有反應性取代基的表面處理劑彼此之混合、具有反應性取代基之表面處理劑與不具有反應性取代基之表面處理劑的混合。 In the film of the present invention, the inorganic particles are preferably treated with a surface treatment agent having a reactive substituent. Specific examples of the surface treatment agent include:

Silane coupling agent, titanium coupling agent, aluminate coupling agent such as oxazoline group, epoxy group, carbodiimide group, acid anhydride group, isocyanate group, etc. Among them, 2-(3,4- Epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyl Silane coupling agents with epoxy groups such as propylpropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, glycidoxyoctyltrimethoxysilane, etc.; 3- Isocyanate propyl triethoxy silane, 3-isocyanatopropyl trimethoxy silane and other silane coupling agents with isocyanate groups; 3-trimethoxysilyl propyl succinic anhydride and other silane coupling agents with acid anhydride groups, etc. Furthermore, an alkoxy oligomer or the like having a reactive substituent is also suitably used. In addition, monomers having epoxy groups such as glycidyl methacrylate, monomers having isocyanate groups such as 2-isocyanate ethyl methacrylate, and styrene, ethylene, propylene, acrylic acid, etc. are preferably used for copolymerization resin; polycarbodiimide, containing

oxazoline-based resin, etc. Among these, when the main component of the film of the present invention is a polyester resin, from the viewpoint that a bond can be formed between the polyester and the inorganic particles to form a strong interface, 2-(3, 4-Epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-epoxy Silane coupling agents with epoxy groups such as propoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, and glycidoxyoctyltrimethoxysilane; Silane coupling agents with isocyanate groups such as 3-isocyanatopropyltriethoxysilane and 3-isocyanatopropyltrimethoxysilane; silane coupling agents with acid anhydride groups such as 3-trimethoxysilylpropyl succinic anhydride ; Alkoxy oligomers with reactive substituents. Furthermore, it is also preferable to use a mixture of the above-mentioned surface-treating agents having a reactive substituent, and a mixture of a surface-treating agent having a reactive substituent and a surface-treating agent having no reactive substituent.

When the inorganic particle content Vf1 (vol%) in the P1 layer is 5~25vol%, it is better because it can improve the thermal conductivity and extensibility of the film, more preferably 7.5~25vol%, and more preferably 10~20vol% %. When the content of the inorganic particles is less than 5% by volume, the contact probability between the inorganic particles becomes low, and as a result, the heat dissipation property may decrease. When the content exceeds 25% by volume, the stretchability of the film and the workability when used as an insulating material or the like may be reduced.

In the film of the present invention, in the cross section of the P1 layer taken perpendicular to the film surface direction and parallel to the film longitudinal direction, when ^{the number of inorganic particles per 10000 μm 2} is defined as Nf (pieces), Nf/Vf1 is 25 or less as good. More preferably, it is 15 or less, and still more preferably 10 or less. When Nf/Vf1 exceeds 25, the probability of contact between inorganic particles decreases, the thermal conductivity of the thin film decreases, the formation of irregularities on the thin film surface due to the inorganic particles becomes insufficient, or the heat dissipation at the interface becomes insufficient. situation. The lower limit of Nf/Vf1 is not particularly limited, but is preferably 1 from the viewpoints of stretchability and windability during film formation.

In the thin film of the present invention, it is preferable that the inorganic particles contained in the P1 layer include inorganic particles with an aspect ratio of 2 or more. The so-called particles with an aspect ratio of 2 or more refer to the primary particles surrounded by a circumscribed cuboid as shown in Figure 1, the longest side of the circumscribed cuboid is defined as the length (l), and the shortest side is defined as the thickness (t) , When the other side is defined as the width (b), the ratio l/t (hereinafter referred to as the aspect ratio) of the length (l) to the thickness (t) is 2 or more. Compared with films containing particles with an aspect ratio of less than 2, the film containing particles with an aspect ratio of 2 or more has a higher contact probability between particles, and the contact probability is higher with a higher aspect ratio. The aspect ratio is more preferably 3 or more, and still higher is 5 or more. Further, the upper limit of the aspect ratio is not particularly limited, but is preferably 40 or less, more preferably 30 or less, from the viewpoint of preventing breakage and cracking of the particles when the inorganic particles are kneaded into the resin.

In the film of the present invention, in the cross section of the P1 layer taken perpendicular to the film surface direction and parallel to the film length direction, the average equivalent circle diameter of the inorganic particles is preferably 3 μm or more, more preferably 5 μm or more, still more preferably is 8 μm or more. The so-called equivalent circle diameter here refers to, The cross-sectional area of the inorganic particles obtained by observing the cross-section is the diameter of the perfect circle when a perfect circle of the same area is drawn. When the average equivalent circle diameter of the inorganic particles is less than 3 μm, the formation of irregularities on the surface of the thin film caused by the inorganic particles is suppressed, and the heat dissipation at the interface may be hindered. The upper limit of the average equivalent circle diameter is preferably 50 μm or less because of the stretchability of the film, and the improvement of the insulating properties and workability when used as an insulating material or the like.

In the thin film of the present invention, the material of the inorganic particles includes, for example, gold, silver, copper, platinum, palladium, rhenium, vanadium, osmium, cobalt, iron, zinc, ruthenium, ruthenium, chromium, nickel, aluminum, tin, zinc , titanium, tantalum, zirconium, antimony, indium, yttrium, lanthanum, silicon and other metals; zinc oxide, titanium oxide, cesium oxide, antimony oxide, tin oxide, indium tin oxide, yttrium oxide, lanthanum oxide, zirconium oxide, aluminum oxide , metal oxides such as magnesium oxide and silicon oxide; metal fluorides such as lithium fluoride, magnesium fluoride, aluminum fluoride, cryolite, etc.; metal phosphates such as calcium phosphate; carbonates such as calcium carbonate; barium sulfate, Sulfates of magnesium sulfate, etc.; nitrides of silicon nitride, boron nitride, carbon nitride, etc.; silicates of wollastonite, sepiolite, vermiculite, etc.; titanium of potassium titanate, strontium titanate, etc. acid, etc.

Moreover, these inorganic particle systems can use 2 or more types.

In view of the fact that the film of the present invention is widely used in applications that require electrical insulation, as for the material of the inorganic particles, zinc oxide, titanium oxide, cesium oxide, antimony oxide, tin oxide, and indium tin oxide are preferably non-conductive. , metal oxides such as yttrium oxide, lanthanum oxide, zirconia, aluminum oxide, magnesium oxide, silicon oxide, etc.; metal fluorides such as lithium fluoride, magnesium fluoride, aluminum fluoride, cryolite, etc.; metal phosphoric acid such as calcium phosphate Salts; carbonates such as calcium carbonate; sulfates such as barium sulfate, magnesium sulfate, etc.; silicon nitride, boron nitride , nitrides such as carbon nitride; silicates such as wollastonite, sepiolite, vermiculite, etc.; titanates such as potassium titanate, etc.

The thickness T of the film of the present invention is preferably 3 μm or more and 500 μm or less, more preferably 5 μm or more and 400 μm or less, and still more preferably 10 μm or more and 300 μm or less. When the thickness is less than 3 μm, the film-forming property of the film is reduced, and the film is often broken during stretching. On the other hand, when the thickness exceeds 500 μm, cutting and bending at the time of use as an insulating material or the like become difficult, and the workability may be lowered. In the thin film of the present invention, by setting the thickness of the thin film to be 3 μm or more and 500 μm or less, it is possible to have both film formability and processability.

The thermal conductivity in the thickness direction of the thin film system of the present invention is preferably 0.15 W/mK or more. More preferably, it is 0.20 W/mK or more, and still more preferably 0.25 W/mK or more. By satisfying this value, it can be applied to copper clad laminates, back sheets for solar cells, adhesive tapes, flexible printed circuit boards, membrane switches, planar heating elements, flat cables, insulating materials for rotating machines, and insulating materials for batteries. Materials that attach importance to electrical insulation and heat dissipation. As a means of improving the thermal conductivity in the thickness direction of the film, a method of obtaining a more preferable raw material formulation as described above, a method of controlling the alignment of molecular chains during stretching, and the like are exemplified.

The surface specific resistance of the thin film system of the present invention is preferably 1×10 ¹³ Ω/□ or more, more preferably 5×10 ¹³ Ω/□ or more. By satisfying this value, it can be used as an electrical insulating material.

The thin-film of the present invention SPc (4000) surface 15 / mm ² or ^more, the surface roughness Ra is preferably more than 100nm, more preferably 300nm or more, and more preferably 500nm or more. When the surface roughness is less than 100 nm, the formation of irregularities on the surface of the thin film due to inorganic particles is suppressed, and heat dissipation at the interface may be hindered. The upper limit of the surface roughness Ra is preferably 3000 nm or less, more preferably 2000 nm or less, in order to prevent the filling of the interface filler from being hindered due to the excessively small protrusion gap. In the present invention, SRa is obtained by the measurement method described later.

The method for setting the SRa on the surface of the film within the above-mentioned range is not particularly limited, but for example, a method of incorporating inorganic particles into the film, using a mold with fine concavo-convex shapes to make the Ra within the above-mentioned range, and applying the method to the film surface processing methods, etc.

The thin film of the present invention is a range from the surface to the thickness of 0.1T on the surface where the thickness of the thin film is set to T (μm) and the number of coarse protrusions SPc (4000) is 15 pieces/mm ^{2 or more.} When the content of inorganic particles is Vfa (volume %), and the inorganic particle content in the range from the thickness 0.1T to the thickness 0.9T is Vfb (volume %), Vfa/Vfb is 0≦Vfa/Vfb< 1 is better. In the present invention, Vfa/Vfb is obtained by the following method, and the smaller the Vfa/Vfb, the smaller the inorganic particle content in the surface layer of the thin film. As a result, the slippage of the inorganic particles from the thin film surface and the occurrence of interfacial peeling at the interface with the inorganic particles can be suppressed. In particular, it has a remarkable effect in the application of bonding thin films to a smooth surface, and it is not easy to cause slippage of inorganic particles and interfacial peeling at the interface of inorganic particles, and it is preferable that the adhesion to the smooth surface can be improved. More preferably, 0.1≦Vfa/Vfb≦8, and still more preferably 0.2≦Vfa/Vfb≦0.5. When Vfa/Vfb is 1 or more, the inorganic particles on the surface may increase, and the inorganic particles may slip off the surface of the film to cause step contamination, or interface peeling may occur at the interface with the inorganic particles. In addition, although the lower limit of Vfa/Vfb is 0, when it is set to 0.1 or more, heat transfer on the surface increases, which is preferable. In addition, since 0≦Vfa/Vfb<1, after controlling the type and surface activity of the inorganic particles, a layer with a small amount of inorganic particles and a layer with a large amount of inorganic particles are stacked to form a layered structure, so as to be arranged on at least one surface. A layer with few inorganic particles is preferred.

The film of the present invention may be a single-layer film composed of only the above-mentioned P1 layer, and a laminated structure in which at least a single-area layer of the P1 layer has other layers (hereinafter, the other layers are also referred to as P2 layers for short) is also applicable. . Among them, in order to prevent the inorganic particles from slipping off the surface of the film or interfacial peeling at the interface with the inorganic particles, it is preferable to laminate a P2 layer with a particle content less than that of the P1 layer on at least one side of the P1 layer. More preferably, it is a laminated structure in which a P2 layer having a particle content smaller than that of the P1 layer can be laminated on both sides of the P1 layer. In this case, from the viewpoint of film-forming properties, it is preferable to make the main component of the P2 layer a polyester resin.

In addition, it is preferable to add inorganic particles to the P2 layer because heat dissipation can be improved, and as the inorganic particles, the above-mentioned ones can be used. At this time, the inorganic particle content Vf2 (volume %) of the P2 layer is such that 0≦Vf1/Vf2 is satisfied between the inorganic particle content Vf1 (volume %) of the P1 layer and the inorganic particle content Vf1 (volume %) of the P1 layer in order for the thin film to satisfy the relationship of 0≦Vfa/Vfb<1 <1 is better. More preferably, 0≦Vf1/Vf2≦0.8, and still more preferably 0≦Vf1/Vf2≦0.5. When Vf1/Vf2 is 1 or more, many particles exist on the surface, and the particles slip off the surface of the film to cause step contamination, or interface peeling occurs at the interface of inorganic particles.

The inorganic particle content Vf2 (volume %) in the P2 layer is preferably 0 to 5 vol % because the stretchability of the film is improved, more preferably 0 to 3 vol %, and still more preferably 0 to 2 vol %. When the content exceeds 5% by volume, The stretchability of the film and the workability when used as an insulating material or the like may be reduced.

The ratio of the P1 layer to the P2 layer is preferably 40% by volume of the entire film, more preferably 50% by volume or more, and still more preferably 70% by volume or more. When the ratio of the P1 layer is less than 40% by volume, the effect of improving the thermal conductivity by the P1 layer may become insufficient.

The thin film of the present invention has high electrical insulating properties, heat dissipation properties and processability. The film of the present invention exerts its function, and can be suitably used as copper-clad laminates, back sheets for solar cells, adhesive tapes, flexible printed circuit boards, membrane switches, planar heating elements, flat cables, insulating materials for rotating machines, It is used as an electrical insulating sheet for insulating materials such as batteries. In particular, when used as an electrical insulating sheet for a rotating machine, the output and efficiency can be improved compared to when using a conventional electrical insulating sheet by improving the heat dissipation of the machine. Furthermore, by utilizing the surface properties of the film, adhesive tapes, release films, transfer films, design sheets, building materials, etc. can also be used.

The elongation at break of the film of the present invention is preferably 10% or more. More preferably, it is 20% or more, and still more preferably 30% or more. In the film of the present invention, when the elongation at break is less than 10%, the film is likely to be broken during film formation, during transportation during continuous processing, or during processing such as cutting. In the film of the present invention, by setting the elongation at break to be 10% or more, it is possible to have both film-forming properties and processability.

The film of the present invention preferably has a burning distance of 125 mm or less when evaluated by the UL94-VTM test method. More preferably, it is 115 mm or less, still more preferably 105 mm or less, especially 100 mm or less, and particularly preferably 95 mm or less. In the film of the present invention, by testing according to UL94-VTM If the burning distance at the time of test method evaluation is 125 mm or less, for example, when it is used as a back sheet for solar cells, it can be used with higher safety.

In the film of the present invention, the SPc (4000) of the film surface is within the required range. When processing the film surface using a mold with a fine concavo-convex shape, as shown in FIG. The mold can be used to improve the heat dissipation on the surface of the film, so it is better. The shape of the mold convex portion may be any of a substantially triangular shape, a substantially quadrangular shape, a substantially hexagonal shape, a circle, an ellipse, and the like. The pitch X of the die protrusions is preferably 20 μm or more and 200 μm or less, and more preferably 50 μm or more and 150 μm or less. When the pitch exceeds 200 μm, the heat dissipation at the interface may be insufficient due to the small number of protrusions on the film surface. When the pitch is less than 20 μm, it may be difficult to impart a concavo-convex shape to the film surface due to processing, and the interval between the imparted protrusions may become too small, resulting in insufficient filling of the interface filler and poor workability. The width Y of the mold protrusions is preferably 0.25 times or more and 0.75 times or less of the pitch X of the mold protrusions, more preferably 0.4 times or more and 0.6 times or less. When the width Y is less than 0.25 times the pitch X, or exceeds 0.75 times, it may be difficult to impart the uneven shape to the surface of the film due to processing. The height Z of the mold convex portion is preferably 5 μm or more, and more preferably 10 μm or more. When the height of the mold convex portion is less than 5 μm, the unevenness provided to the surface of the film becomes gentle, so that the heat dissipation at the interface becomes insufficient. Furthermore, as for the film to be processed, it is preferable to use a film whose area stretching ratio at the time of stretching is 10 times or less, more preferably 8 times or less. When a film having an area magnification of more than 10 times is used, the provision of unevenness on the surface of the film may become insufficient due to processing.

Next, the method for producing the thin film of the present invention will be described An example of the case where the main component is a polyester resin is not to be interpreted as being limited to this example.

(Step 1: Polymerization of polyester)

The polyester system can be obtained by carrying out a polycondensation reaction of the above-mentioned dicarboxylic acid constituents and diol constituents through an esterification reaction or a transesterification reaction, so that the intrinsic viscosity is 0.4 or more. When performing the transesterification, in addition to using conventional transesterification catalysts such as magnesium acetate, calcium acetate, manganese acetate, cobalt acetate, calcium acetate, etc., antimony trioxide and the like can also be added as a polymerization catalyst. During the esterification reaction, when several ppm of alkali metals such as potassium hydroxide are added in advance, by-products of diethylene glycol can be suppressed, and heat resistance and hydrolysis resistance can also be improved.

Moreover, as a polycondensation reaction catalyst, the ethylene glycol solution of germanium dioxide, antimony trioxide, a titanium alkoxide, a titanium chelate compound, etc. can be used.

Other additives include, for example, magnesium acetate for the purpose of imparting electrostatic application properties, calcium acetate as a co-catalyst, and the like, and may be added within a range that does not inhibit the effects of the present invention. Furthermore, in order to impart smoothness to the thin film, various particles may be added, or internally precipitated particles using a catalyst may be contained.

(Step 2: Surface Treatment of Inorganic Particles)

When the inorganic particles are surface-treated, the inorganic particles include i) a method of dispersing the particles in a solvent and then adding a surface-treating agent, or a solution/dispersion in which the surface-treating agent is dissolved/dispersed while stirring the dispersion. , ii) A method of adding a solution/dispersion for dissolving/dispersing the surface treatment agent while stirring the powder of inorganic particles. Moreover, the surface When the treating agent is resin-based, it is also preferable to use the method of iii) melt-kneading the inorganic particles and the surface treating agent. When the weight of the inorganic particles is set to 100 parts by mass, the addition amount of the surface treatment agent is preferably 0.1 part by mass or more and 5 parts by mass or less. More preferably, it is 0.2 mass parts or more and 3 mass parts or less, and still more preferably 0.5 mass parts or more and 1.5 mass parts or less. When the content is less than 0.1 part by mass, when the polyester and the inorganic particles are melt-kneaded in the subsequent step, the bonding between the polyester and the inorganic particles becomes insufficient, interfacial peeling occurs during extension, and thermal conductivity is lowered. Furthermore, when it exceeds 5 mass parts, the amount of bonding becomes too large and the elongation is lowered.

(Step 3: Manufacture of polyester resin composition)

The polyester obtained in the above-mentioned step 1 contains the inorganic particles obtained in the above-mentioned step 2 to obtain a polyester resin composition. Preferably, the polyester and the inorganic particles are preliminarily kneaded using a vented biaxial kneading extruder or A method of melt-kneading with tandem extruders. At this time, in order not to damage the shape of the inorganic particles during melt-kneading, the polyester is preferably supplied in a molten state to the inorganic particles, and preferably supplied to the extruder from a side feed.

Moreover, when melt-kneading polyester-containing inorganic particles is subjected to a thermal history, a lot of polyester is deteriorated. Therefore, compared with the content of inorganic particles in the P1 layer, a high concentration master pellet (Master pellet) with a large amount of addition is made, mixed with polyester and diluted, and the amount of inorganic particles in the P1 layer is made into the desired content. In this case, the deterioration of the polyester can be suppressed, which is preferable from the viewpoints of elongation, mechanical properties, heat resistance, and the like. Moreover, compared with the content of the inorganic particles in the P1 layer, using the high concentration masterbatch particles with a large amount of addition after solid-phase polymerization can increase the molecular weight and further reduce the number of carboxyl end groups. good. solid state polymerization In the combination, the solid-phase polymerization reaction is preferably carried out at a temperature of solid-phase polymerization below the melting point Tm-30°C of polyester, above the melting point Tm-60°C, and vacuum degree below 0.3 Torr.

(Step 4: Fabrication of Film)

When the film of the present invention consists only of a single film of the P1 layer, the raw material for the P1 layer is heated and melted in an extruder, and is extruded from a nozzle on a cooled casting drum to form a sheet (melt casting method). As another method, the raw material for the P1 layer is dissolved in a solvent, the solution is extruded from a nozzle on a support such as a casting drum, an endless belt, etc. to form a film, and then the solvent is dried from the film layer. A method of removing and processing into flakes (solution casting method), etc. Among them, from the viewpoint of high productivity, it is preferable to form into a sheet by a melt casting method (hereinafter, the step of forming into a sheet by a melt casting method is referred to as a melt extrusion step).

In the melt extrusion step, after drying the composition containing polyester and inorganic particles, it is melt extruded from a nozzle into a film using an extruder, and cooled to a surface temperature of 10°C or more and 60°C or less on a roller. It solidifies by electrostatic adhesion cooling, and produces an unstretched sheet.

When melt extruding from the extruder, melt in a nitrogen atmosphere, and the time from supplying the small pieces to the extruder to extruding to the nozzle is as short as possible, and the target is set to 30 minutes or less, more preferably 15 minutes or less, Still more preferably, it is 5 minutes or less, and it is more preferable from the viewpoints of suppressing deterioration due to a decrease in molecular weight and suppressing an increase in the number of carboxyl terminal groups.

In addition, when the film of the present invention has a layered structure including the P2 layer, two different materials may be fed into two extruders, melted, laminated before being discharged from a nozzle, and co-extruded into a sheet.

Next, the unstretched sheet obtained above is biaxially stretched at a temperature equal to or higher than the glass transition temperature Tg. The method of biaxial stretching may be any of the sequential biaxial stretching method in which the stretching in the longitudinal direction and the width direction is separated, and the simultaneous biaxial stretching method in which the stretching in the longitudinal direction and the width direction is carried out simultaneously. By. As an example of the stretching conditions, 1) in the case of simultaneous biaxial stretching, the stretching temperature is set to a temperature in the range of the glass transition temperature Tg of polyester or higher and Tg+15°C or lower, and 2) in the case of successive biaxial stretching, The stretching temperature of the first axis is set to be the glass transition temperature Tg of polyester or more and Tg+15°C or less (more preferably Tg or more and Tg+10°C or less), and the stretching temperature of the second axis is set to Tg+5°C Above Tg+25℃ or below temperature.

The stretching ratio is 1.5 times or more and 3.5 times or less in the longitudinal direction and the width direction in both simultaneous biaxial stretching and successive biaxial stretching. More preferably, it is 2.0 times or more and 3.0 times or less. Furthermore, the area stretching ratio combining the stretching ratio in the longitudinal direction and the stretching ratio in the lateral direction is 2 times or more and 12 times or less, more preferably 4 times or more and 10 times or less. When the area elongation ratio is less than 2 times, the orientation of the obtained film is low, and the mechanical strength and heat resistance may be lowered. In addition, when the area stretching ratio exceeds 12 times, cracks are likely to occur during stretching, the porosity of the obtained film tends to increase, and the thermal conductivity tends to decrease.

Next, in order to sufficiently advance the crystal orientation of the obtained biaxially stretched film and impart planarity and dimensional stability, a heat treatment is performed at a temperature Th of not less than the glass transition temperature Tg of the polyester and not more than the melting point Tm of the polyester for 1 second or more and 30 seconds or less. , and after cooling slowly evenly, cool to room temperature. In the production method of the film of the present invention, the heat treatment temperature Th and the melting point of the polyester The point Tm difference Tm-Th is 20°C or higher and 90°C or lower, preferably 25°C or higher and 70°C or lower, more preferably 30°C or higher and 60°C or lower. Furthermore, in the above-mentioned heat treatment step, a relaxation treatment of 3 to 12% may be performed in the width direction or the length direction as needed, and then, as needed, a corona discharge treatment, etc. may also be performed in order to further improve the adhesion with other materials. winding, thereby obtaining the film of the present invention.

Furthermore, when the surface of the film is processed using a mold having a fine concavo-convex shape, a method of using a casting roll, a stretching roll, or a stretching roll having a fine concavo-convex shape during film formation, or a method of obtaining a biaxially stretched film, using a fine concavo-convex shape A method of pressing a mold of the shape into a film, etc.

Next, the production method of the present invention will be described as an example when the main component is a polyarylene sulfide resin, but the present invention is not limited to this example.

(Step 1: Polymerization of polyphenylene sulfide)

Sodium sulfide and p-dichlorobenzene are reacted under high temperature and high pressure in an amide-based polar solvent such as N-methyl-2-pyrrolidone (NMP). A copolymerization component including trihalobenzene and the like can also be used as required. A caustic alkali, an alkali metal carboxylate, etc. are added as a polymerization degree adjuster, and the polymerization reaction is carried out at 230°C to 280°C.

After the polymerization, the polymer was cooled, and the polymer was filtered through a filter as an aqueous slurry to obtain a granular polymer. This is stirred in an aqueous solution of acetate or the like at 30°C to 100°C for 10 to 60 minutes, washed several times in ion-exchanged water at 30 to 80°C, and dried to obtain PPS powder. The powder polymer is washed in NMP under an oxygen partial pressure of 10 Torr or less, preferably 5 Torr or less, and then separated at a temperature of 30 to 80 °C. The sub-exchange water was washed several times and dried under a reduced pressure below 5 Torr. Since the powder polymer thus obtained is substantially a linear PPS polymer, it can be stably extended to form a film.

(Step 2: Surface Treatment of Inorganic Particles)

When the inorganic particles are surface-treated, the inorganic particles are i) a method of dispersing the particles in a solvent and then adding a surface-treating agent or a solution/dispersion in which the surface-treating agent is dissolved/dispersed while stirring the dispersion, ii ) A method of adding a solution/dispersion for dissolving/dispersing a surface treating agent while stirring the powder of inorganic particles, etc. In addition, when the surface treating agent is resin-based, the method of iii) melt-kneading the inorganic particles and the surface treating agent is also applicable. The addition amount of the surface treatment material is preferably 0.1 part by mass to 5 parts by mass when the weight of the inorganic particles is 100 parts by mass.

(Step 3: Manufacture of polyphenylene sulfide resin composition)

The method for obtaining a polyphenylene sulfide resin composition containing the inorganic particles obtained in the above-mentioned step 2 from the polyphenylene sulfide obtained in the above-mentioned step 1 is preferably to use an exhaust-type dual A method of melt kneading with a shaft kneading extruder or a tandem extruder. At this time, in order to prevent the shape of the inorganic particles from being damaged during melt-kneading, polyphenylene sulfide is preferably supplied to the inorganic particles in a molten state, and preferably supplied to the extruder by side feed. The intestine-shaped polymer discharged from the extruder is cooled in a water bath according to the usual method, and then cut to form particles dispersed in the polymer (hereinafter, the particles may also be referred to as particle particles). . Furthermore, only the polyphenylene sulfide powder obtained in the above-mentioned step 1 is granulated (hereinafter, the granules may also be referred to as non-particle granules). It is mixed with particles and particles when making films.

(Step 4: Fabrication of Film)

The particles and/or particle-free particles obtained in the above step 3 are dried under reduced pressure, and then put into the melting part of the extruder and heated to a temperature of 300-350°C, preferably an extruder of 310-340°C. Then, the molten polymer passed through the extruder was passed through the filter, and the molten polymer was discharged into a sheet shape using the nozzle of the T-die. The setting temperature of the filter part and the interface device is preferably set at a temperature higher than the melting temperature of the extruder by 3-20°C, more preferably 5-15°C higher. The sheet-like object was adhered to a cooling roller with a surface temperature of 20 to 70° C., and cooled and solidified to obtain an unstretched film in a substantially unaligned state.

Next, the unstretched film is biaxially stretched for biaxial alignment. In terms of the stretching method, a sequential biaxial stretching method, a simultaneous biaxial stretching method, or a combination of these methods can be used. Here, an example of using the successive biaxial stretching method will be described.

After the unstretched film is heated by the heating roll group, it is stretched at a stretching ratio of 1.5 times or more and 3.5 times or less in the longitudinal direction and the width direction, respectively. More preferably, it is 2.0 times or more and 3.0 times or less. Furthermore, the area stretching ratio combining the stretching ratio in the longitudinal direction and the stretching ratio in the lateral direction is 2 times or more and 12 times or less, more preferably 4 times or more and 10 times or less. When the area stretching ratio is less than 2 times, the orientation of the obtained film may be low, and the mechanical strength and heat resistance may be reduced. In addition, when the area stretching ratio exceeds 12 times, breakage is likely to occur during stretching, or the porosity of the obtained film tends to increase, and the thermal conductivity tends to decrease. The extension temperature is preferably 70 to 130°C, more preferably 80 to 110°C.

Next, the biaxially stretched film is heat-treated under tension. The heat treatment temperature is preferably in the range of 160 to 280° C., and is carried out in one stage or more than two stages. In this case, it is preferable from the viewpoint of thermal dimensional stability that the relaxation treatment is performed in the range of 0 to 10% in the width direction of the film at the heat treatment temperature. When two-stage heat treatment is performed, the heat treatment temperature of the first stage is set in the range of 160~220°C, and the heat treatment temperature of the second stage is set in the range of 230~280°C, which is higher than the temperature of the first stage. It is better to improve the flatness of the film and to stabilize the film formation. After heat treatment, the film was cooled to room temperature. Then, as required, in order to further improve the adhesiveness with other materials, corona discharge treatment can be performed, and the film of the present invention can be obtained by winding.

[Evaluation method of characteristics]

A. Composition Analysis of Polyester

The polyester is hydrolyzed by alkali, each component is analyzed by a gas chromatograph or a high performance liquid chromatograph, and the composition ratio is obtained from the peak area of each component. An example is shown below. The dicarboxylic acid constituent or other constituents are measured by high performance liquid chromatography. The measurement conditions can be analyzed by conventional methods, and an example of the measurement conditions is shown below.

Device: Shimadzu LC-10A

Column: YMC-Pack ODS-A 150×4.6mm S-5μm 120A

Column temperature: 40℃

Flow: 1.2ml/min

Detector: UV 240nm

Gas can be used for quantitative determination of glycol constituents and other constituents phase chromatograph and analyzed by conventional methods. An example of measurement conditions is shown below.

Installation: Shimadzu 9A (manufactured by Shimadzu Corporation)

Column: SUPELCOWAX-10 capillary column 30m

Column temperature: 140°C~250°C (heating rate 5°C/min)

Flow: Nitrogen 25ml/min

Detector: FID.

B. Intrinsic Viscosity IV

The film was dissolved in 100 ml of o-chlorophenol (resin concentration in the solution C=1.2 g/ml), and the viscosity of the solution at 25°C was measured using an Ostrich viscometer. Furthermore, the viscosity of the solvent was measured in the same manner. Using the obtained solution viscosity and solvent viscosity, [η] was calculated from the following formula (1), and the obtained value was defined as the intrinsic viscosity [IV].

ηsp/C=[η]+K[η] ² . C (1)

(where, ηsp=(viscosity of solution/viscosity of solvent))-1, K is the Huggins constant (0.343)). In addition, measurement is implemented after isolation|separation of insoluble components, such as an inorganic particle.

C. Glass transition temperature Tg, melting point Tm, crystal fusion heat △Hm

The film was measured according to JIS K-7121 (1987) and JIS K-7122 (1987), and the measuring device was a differential scanning calorimeter "Robot DSC-RDC220" manufactured by Seiko Electronics Co., Ltd. for data analysis using Disk The session "SSC/5200" was measured according to the following method.

(1) The first operation measurement

Weigh 5 mg of each film sample in the sample pan, and the heating rate is The resin was heated from 25°C to 300°C (320°C in the case of PPS resin) at a temperature increase rate of 20°C/min at 20°C/min, maintained in this state for 5 minutes, and then quenched so that it became 25°C or lower.

(2) The second operation

Immediately after the completion of the first run measurement, the measurement was performed again from 25°C to 300°C (320°C in the case of PPS resin) at a temperature increase rate of 20°C/min. In the differential scanning calorimetry chart obtained for the second run, the glass transition temperature was obtained according to the method described in JIS K-7121 (1987) (a straight line extending from each reference line is equidistant in the vertical axis direction, Obtained from the intersection point of the curve with the phase-like change portion of the glass transition). In addition, the peak top temperature of the crystal melting peak was also taken as the melting point Tm, and the crystal melting heat ΔHm was determined according to the method described in JIS K-7122 (1987).

D. Elongation at break

The breaking elongation of the film is based on ASTM-D882 (1997), the sample is cut into a size of 1 cm×20 cm, and the breaking elongation is measured when the clip is stretched at 5 cm and the extension speed is 300 mm/min. In the measurement, any direction of the film is set to 0°, and samples are cut out from -90° to 90° in the film plane every 10°, and the direction in which the elongation at break becomes the smallest is defined as the longitudinal direction of the film. The average value of the elongation at break in the longitudinal direction and the elongation at break in the direction orthogonal to the longitudinal direction was taken as the elongation at break of the film.

E. Coarse protrusion number SPc (4000), surface roughness SRa

The surface morphology was measured under the following conditions according to JIS-B0601 (1994) using a high-definition micro-shape measuring device (three-dimensional surface roughness meter) of the stylus method, and the surface roughness SRa was calculated.

Measuring device: 3-dimensional micro-shape measuring device (type ET-4000A) Kosaka Research Institute (stock) system

Analysis Machine: 3D Surface Roughness Analysis System (Type TDA-31)

Stylus: tip radius 0.5μmR, diameter 2μm, diamond

Needle pressure: 100μN

Measurement direction: average after measuring the film length direction and film width direction once each

X measurement length: 1.0mm

X feeding speed: 0.1mm/s (measurement speed)

Y feed pitch: 5 μm (measurement interval)

Number of Y lines: 81 (measurement number)

Z magnification: 20 times (vertical magnification)

Low frequency cutoff: 0.20mm (waveform cutoff value)

High frequency cutoff: R+Wmm (coarse cutoff value)

(R+W system has no cut-off)

Filter method: Gaussian space type

Leveling: Yes (tilt correction)

Base area: 1mm ² .

The number of coarse protrusions SPc(4000) represents the number of protrusions per reference area of 4000 nm or more, and was calculated in the analysis system with the following settings.

Slice level condition setting: fixed upper and lower intervals

Center pitch level: 0.05μm

Up and down horizontal interval: 0.025μm

Lower limit: 3975nm

Center level: 4000nm

Upper limit: 4025nm.

F. Porosity Va

The porosity in the P1 layer is obtained according to the following steps (A1) to (A5). In addition, the measurement was performed 10 times in total by randomly changing the film cut position, and the arithmetic mean value was used as the void ratio Va (volume %) of the P1 layer.

(A1) Using a microtome, the cross section of the film is cut perpendicular to the film surface direction without being flattened in the thickness direction, and the film is cut parallel to the longitudinal direction of the film (the direction defined by the measurement of elongation at break).

(A2) Next, the cut section was observed with a scanning electron microscope, and an image observed at a magnification of 3000 times was obtained. In addition, the observation point is randomly determined in the P1 layer, and the vertical direction of the image is parallel to the thickness direction of the film, and the left-right direction of the image is parallel to the longitudinal direction of the film.

(A3) Measure the area of the P1 layer in the image obtained in the above (A2) (including the entire area of the voids and the area of the inorganic particles existing in the P1 layer), and set this as A. In addition, when it is difficult to distinguish the interface between the P1 layer and other layers in the image, in the same way, the cross-section of the sample is observed using a differential interference microscope to search for the interface position of the P1 layer, and the area of the P1 layer is estimated.

(A4) Measure the total void area present in the P1 layer in the image, and set the total area as B. Here, as the measurement object, not only the entire voids are included in the image, but the air bubbles that appear only partially are also included in the image.

(A5) Divide B by A (B/A), and multiply this by 100 to obtain the area ratio of the voids in the P1 layer, and use this value as the void ratio Va (volume %).

G. Inorganic particle content Vf1 in P1 layer, number Nf of inorganic particles, average equivalent circle diameter of inorganic particles

The inorganic particle content Vf1 in the P1 layer, the number of inorganic particles Nf, and the average equivalent circle diameter of the inorganic particles are obtained according to the following steps (B1) to (B7). In addition, the measurement is carried out 10 times in total by randomly changing the cut position of the film, and the arithmetic mean value is taken as the inorganic particle content Vf1 (volume %), the number of inorganic particles Nf (pieces), and the number of inorganic particles in the P1 layer, respectively. Average equivalent circle diameter (μm).

(B1) Using a slicer, the cross section of the film is cut perpendicular to the film surface direction without being flattened in the thickness direction, and the film length direction (the direction defined by the measurement of elongation at break) is cut parallel to the film.

(B2) Next, the cut cross section was observed with a scanning electron microscope, and an image observed at a magnification of 3000 times was obtained. In addition, the observation point is randomly determined in the P1 layer, and the vertical direction of the image is parallel to the thickness direction of the film, and the left-right direction of the image is parallel to the longitudinal direction of the film.

(B3) Measure the area of the P1 layer in the image obtained in the above (B2) (including the entire area of the voids and the area of the inorganic particles existing in the P1 layer), and set this as A. In addition, when it is difficult to distinguish the interface between the P1 layer and other layers in the image, in the same way, the cross-section of the sample is observed using a differential interference microscope to search for the interface position of the P1 layer, and the area of the P1 layer is estimated.

(B4) The area of all the inorganic particles present in the P1 layer in the image is measured, and the total area is set to C. Here, the measurement object is not limited to the inclusion of the entire inorganic particles in the image, and the inorganic particles that appear only partially are also included in the image. Furthermore, when it is difficult to determine the position of the inorganic particles in the image, similarly, energy dispersive X-ray analysis is performed on the cross section of the sample, and the area is calculated after determining the portion including the inorganic matter.

(B5) Divide C by A (C/A), and by multiplying here by 100, obtain the P1 layer The area ratio of the inorganic particles inside is taken as the inorganic particle content Vf1 (volume %).

(B6) In (B4), the number of all observed inorganic particles is calculated as the number Nf of inorganic particles.

In (B7) and (B4), each area of the observed inorganic particles is obtained, and the area and the diameter of a perfect circle that draws the same area are used as the equivalent circle diameter (μm) of the inorganic particles. After calculating the equivalent circle diameter for all the observed particles, the arithmetic mean of these was used as the average equivalent circle diameter (μm).

H. Thin film thickness T (μm), inorganic particle content Vfa (volume %) ranging from the film surface to thickness 0.1T, inorganic particle content Vfb (volume %) ranging from thickness 0.1T to thickness 0.9T

The thickness T (μm) of the film, the inorganic particle content Vfa (volume %) in the range from the film surface to the thickness 0.1T, and the inorganic particle content Vfb (volume %) in the range from the thickness 0.1T to 0.9T are as follows ( C1) ~ (C7) steps to obtain. In addition, the measurement was carried out 10 times in total by randomly changing the cut position of the film, and the arithmetic mean value was used as the thickness T (μm) of the film and the inorganic particle content Vfa (volume) in the range from the film surface to the thickness of 0.1T, respectively. %), the inorganic particle content Vfb (volume %) in the range from thickness 0.1T to thickness 0.9T.

(C1) Using a slicing machine, the cross section of the film is not flattened in the thickness direction to cut perpendicular to the film surface direction and parallel to the longitudinal direction of the film (the direction defined by the measurement of elongation at break).

(C2) Next, the cut section was observed with a scanning electron microscope, and an image observed at a magnification of 3000 times was obtained. In addition, the observation point is randomly determined, but the upper and lower directions of the image and the thickness direction of the film are respectively set. , The left and right direction of the image is parallel to the length direction of the film. Furthermore, it is performed by moving the observation point in the thickness direction, and a continuous image from one surface to the other surface is prepared.

(C3) In the image obtained in the above (C2), the area from the surface to the thickness of 0 to 0.1 T (the entire area including the area of voids and inorganic particles existing in the thin film) is measured, and this is defined as Aa. And similarly, the area from the surface to the range of thickness 0.1T-0.9T was measured, and the total area was made into Ab.

(C4) In the thin film in the image, the area of all the inorganic particles in the range from the surface to the thickness of 0 to 0.1 T was measured, and the total area was defined as Ba. Here, as the measurement object, not only the entire inorganic particles in the range of thickness 0 to 0.1 T are included in the image, but the inorganic particles only partially appearing are also included in the image. In addition, when it is difficult to distinguish inorganic particles in the image, in the same manner, energy dispersive X-ray analysis is performed on the cross section of the sample, and the area is calculated after identifying the portion composed of inorganic substances. Furthermore, the area of all the inorganic particles in the range from the surface to the thickness of 0.1T to 0.9T was measured in the same manner, and the total area was defined as Bb.

(C5) Divide Ba by Aa (Ba/Aa), and multiply here by 100 to obtain the area ratio of inorganic particles ranging from the surface to the thickness of 0 to 0.1T, and use this value as the value from the surface to the thickness of 0.1 Inorganic particle content Vfa (volume %) in the range of T. And similarly, divide Bb by Ab (Bb/Ab), and multiply here by 100, and set it as content Vfb (vol%) of the inorganic particle in the range of 0.1T-0.9T. In addition, the thickness T (μm) of the thin film was measured using a dial gauge in accordance with JIS K7130 (1992) A-2 method at any five places in a state where ten thin films were stacked. The average value was divided by 10 to obtain the thickness T (μm) of the thin film.

I. Thermal conductivity in the thickness direction of the film

After measuring the thickness of the film using a flat-tip dial gauge thickness gauge (manufactured by Mitsutoyo Co., Ltd.), aluminum was deposited on both sides of the film using a bell jar deposition machine. The deposition thickness is the thickness when the laser light from the laser pointer is irradiated from one side of the film, and the thickness when the laser light is no longer transmitted is observed with the naked eye from the opposite side. Next, a spray for laser light absorption (Black guard spray FC-153 manufactured by Fine Chemical Japan Co., Ltd.) was applied thinly on both sides and dried, and then a 10 mm square sample was cut out and manufactured by NETZSCN using a Xe flash lamp analyzer. The LFA467 Nanoflash was used to measure the thermal diffusivity α (m ² /s) in the thickness direction of the film at a measurement temperature of 25°C. Then, the measurement system was carried out four times, and the average value was used as the thermal diffusivity, and the thermal conductivity was obtained by the following formula (2).

Thermal conductivity (W/mK)=α(m ² /s)×specific heat (J/kg．K)×density (kg/m ³ ) (2)

In addition, the specific heat system used the value calculated|required based on JIS K-7123 (1987). In addition, the density is a sample cut into a size of 30mm × 40mm using a film, and an electronic hydrometer (SD-120L manufactured by Mirage Trading Co., Ltd.) is used at room temperature of 23°C and relative humidity of 65%. The environment is carried out 10 times. For measurement, the obtained average value was used.

J. Surface specific resistance

The surface specific resistivity of the thin film was measured with a digital ultra-high-resistance microcurrent meter R8340 (manufactured by Advantest Co., Ltd.). The measurement was carried out on each of both surfaces of the film, and the measurement was performed at arbitrary 10 places in the surface, and the average value was obtained for each. The obtained average value was taken as the surface specific resistance which was the lower value. In addition, the measurement sample was used in a room of 23°C, 65%Rh and humidity-conditioned for 24 hours. . Use the obtained value and determine as follows. A and B series practical range.

A: Surface specific resistance is 5×10 ¹³ Ω/□ or more

B: The surface specific resistance is 1×10 ¹³ Ω/□ or more and less than 5×10 ¹³ Ω/□

D: The surface specific resistance is less than 1×10 ¹³ Ω/□.

K. Electrical Insulation

On both sides of the film, a thermosetting adhesive was uniformly applied so that the thickness after drying was 5 μm, and “Nomex” (registered trademark) (Type 410 of DuPont Teijin Advanced Paper Co., Ltd.) was applied to both sides of the film through the adhesive. , thickness 50μm) with a hot press.

The obtained laminate was cut into a square of size 25cm×25cm, and the humidity was adjusted in a room of 23°C and 65%Rh for 24 hours. According to JIS C2151 (2006), an AC breakdown tester (manufactured by Kasuga Electric Co., Ltd., AC30kV) was used. , measure the dielectric breakdown voltage (kV/mm) per unit thickness at a frequency of 60Hz and a boosting speed of 1000V/sec. In addition, the thickness of the laminated body was measured using a flat-tip dial gauge thickness gauge (manufactured by Mitsutoyo Co., Ltd.). The electrical insulating properties were evaluated according to the following criteria. Series A and B are suitable for use as materials with high electrical insulating properties.

A: The dielectric breakdown voltage is above 150kV/mm

B: The dielectric breakdown voltage is more than 100kV/mm and less than 150kV/mm

D: The dielectric breakdown voltage is less than 100kV/mm.

L. Heat dissipation

On both sides of the film, a thermosetting adhesive was uniformly applied so that the thickness after drying was 5 μm, and “Nomex” (registered trademark) (Type 410 of DuPont Teijin Advanced Paper Co., Ltd.) was applied to both sides of the film through the adhesive. , thickness 50μm) with a hot press.

The obtained layered product was cut into a plurality of circular shapes with a diameter of 8 cm, stacked so that the thickness was in the range of 1 to 1.5 mm, and placed on a surface heat source (3W) with a diameter of 3 cm at a room temperature of 25°C to make the layered product. set for single-sided close contact. In addition, when installing, the center of the layered body is placed at the center, and the interface between the layered body and the surface heat source and the interface between the layered bodies are thinly coated with a heat sink manufactured by Shin-Etsu Chemical Co., Ltd. Silicone grease (G-775) to make the interface tightly bonded so that no air is mixed in the interface. Five minutes after the start of the setting, the surface temperature of the heat source and the laminate on the opposite side was measured using a thermal imaging method (manufactured by Nippon Avionics Co., Ltd.). The measurement positions correspond to the center of the circle of the laminated body, and two places correspond to the ends of the circle of the laminated body. The temperature at the center of the circle is Tc (°C), and the temperature at the end of the circle is set as Tc (°C), respectively. The temperature is set as Te (°C). The smaller the temperature difference between Tc and Te, means that the heat diffuses around and relieves the hot spot, and the heat dissipation is evaluated according to the following criteria. A to C series are suitable as materials with high heat dissipation.

A: Tc-Te is less than 10℃

B: Tc-Te is 10°C or more and less than 15°C

C: Tc-Te is 15°C or more and less than 20°C

D: Tc-Te is 20°C or higher.

M. Processability

On both sides of the film, a thermosetting adhesive was uniformly applied so that the thickness after drying was 5 μm, and “Nomex” (registered trademark) (Type 410 of DuPont Teijin Advanced Paper Co., Ltd.) was applied to both sides of the film through the adhesive. , thickness 50μm) with a hot press.

Next, the obtained layered product was subjected to the Scott rubbing abrasion test. machine (manufactured by Toyo Seiki Kogyo Co., Ltd.), and a friction test was carried out in accordance with JIS-K-6328. The size of the sample is 10 mm in width and 200 mm in length, measured with a load of 2.5 kg, and the number of times of cracking or breakage at the laminate interface can be confirmed with the naked eye. Workability was determined according to the following criteria. A and B are in the practical range.

A: More than 100 times

B: 50 times or more and less than 100 times

C: less than 50 times

N. Adhesion to smooth surfaces

On both sides of the film, a thermosetting adhesive was uniformly applied so that the thickness after drying was 5 μm, and the PPS film “Torelina” (registered trademark) (3030) made by Toray Co., Ltd. was applied to both sides of the film through the adhesive. type, thickness 16 μm) and lamination with a hot press. Cut into samples with a width of 10mm and a length of 200mm, and put the samples in a tensile testing machine manufactured by Taiei Science Precision Manufacturing Co., Ltd. under the conditions of a speed of 200mm/min and a peeling angle of 180°, in accordance with JIS K 6854-2 (1999 ) to measure. From the obtained measurement data of the peeling length (mm) and peeling load (N), the optimum load straight line was derived according to the optimum linear method, and the 180° peel strength was obtained. Adhesion to the smooth surface was determined according to the following criteria. A and B are practically better.

A: 3.0N/cm or more

B: 1.0N/cm or more and less than 3.0N/cm

C: Less than 1.0 N/cm.

[Example]

Hereinafter, the present invention will be described with reference to a series of embodiments, but the present invention is not limited to these.

(Reference Example 1-1)

Using dimethyl terephthalate as an acid component, using ethylene glycol as a dihydric alcohol, and using germanium oxide as a polymerization catalyst, a polycondensation reaction was performed to obtain polyester particles with an intrinsic viscosity of 0.65. Furthermore, the glass transition temperature Tg of the polyester thus obtained was 83°C, the melting point Tm was 255°C, and the heat of crystal fusion was 37 J/g.

(Reference Example 1-2)

Feed into the autoclave 9.44kg (80 moles) of 47% sodium hydrosulfide, 3.43kg (82.4 moles) of 96% sodium hydroxide, 13.0kg (131 moles) of N-methyl-2-pyrrolidone (NMP). ear), sodium acetate 2.86kg (34.9 moles) and 12kg of ion-exchanged water, slowly heated to 235 ° C for 3 hours by nitrogen gas under normal pressure, after the distillation of water 17.0kg and NMP 0.3kg (3.23 moles) , the reaction vessel was cooled to 160 °C. Next, 11.5 kg (78.4 mol) of p-dichlorobenzene (p-DCB) as the main monomer, 0.007 kg (0.04 mol) of 1,2,4-trichlorobenzene as the sub-component monomer were added, and then 22.2 kg (223 moles) of NMP was added, the reaction vessel was sealed under nitrogen, and the temperature was increased from 200°C to 270°C at a rate of 0.6°C/min while stirring at 400 rpm. After 30 minutes at 270°C, 1.11 kg (61.6 mol) of water was injected into the system for 10 minutes, and the reaction was further continued at 270°C for 100 minutes. Then, 1.60 kg (88.8 moles) of water was injected into the system again, cooled to 240°C, then cooled to 210°C at a rate of 0.4°C/min, and then quenched to around room temperature. The contents were taken out and diluted with 32 liters of NMP, and then the solvent and solids were filtered through a sieve (80 mesh). The resulting particles were washed again with 38 liters of NMP at 85°C. Then, it wash|cleaned 5 times with 67 liters of warm water, and carried out separate filtration, and also washed five times with 70,000 g of 0.05 mass % calcium acetate aqueous solution, and carried out separate filtration. By drying the obtained particles with hot air at 60°C, Drying under reduced pressure was carried out at 120° C. for 20 hours to obtain white particles of PPS resin. The glass transition temperature Tg of the powder system of the obtained PPS resin was 92°C, the melting point Tm was 280°C, and the heat of crystal fusion was 33 J/g.

(Reference Example 2-1)

Put the wollastonite particles with an average particle size of 17 μm and an aspect ratio of 4 (made by Kaihe Furnace Materials Co., Ltd., K400) into a Henschel mixer and stir, in this state, to 100 mass of wollastonite particles. % of silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-403) was sprayed and added to 1% by mass, heated and stirred at 70°C for 2 hours, and then taken out to obtain a surface-treated silicon limestone particles.

(Reference Example 2-2)

Silica particles with an average particle size of 1 μm and an aspect ratio of 1 were put into a Henschel mixer and stirred, and in this state, 100% by mass of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.) was added to the wollastonite particles. KBM-403) was added by spraying the silane coupling agent so as to be 1 mass %, and after heating and stirring at 70° C. for 2 hours, it was taken out to obtain surface-treated silicon oxide particles.

(Reference Example 2-3)

The wollastonite particles with an average particle size of 30 μm and an aspect ratio of 4 (manufactured by Kinsei Matec Co., Ltd., FPW #150) were put into a Henschel mixer and stirred. % of silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-403) was sprayed and added to 1% by mass, heated and stirred at 70°C for 2 hours, and then taken out to obtain a surface-treated silicon limestone particles.

(Reference Example 3-1)

The mixing paddle with more than 1 side feed port and 1 position will be kneaded The co-rotating type vented twin-shaft kneading extruder (made by Nippon Steel, screw diameter 30mm, screw length/screw diameter = 45.5) was heated to 265°C, and the reference example 1- 60 parts by mass of the polyester obtained in 1, 40 parts by mass of the surface-treated wollastonite particles obtained in Reference Example 2-1 were supplied from the side feed port, and after being melted and kneaded, they were spit out into strands, and the temperature was 25°C. After cooling in hot water, it was cut immediately to make master batch particles containing 40% by weight of wollastonite particles.

(Reference Example 3-2)

A co-rotating type vented twin-shaft kneading extruder (manufactured by Nippon Steel, screw diameter 30 mm, screw length / screw Diameter=45.5) was heated to 265°C, 90 parts by mass of the polyester obtained in Reference Example 1-1 was supplied from the main feed port, and the surface-treated silicon oxide particles obtained in Reference Example 2-2 were supplied from the side feed port 10 parts by mass were melted and kneaded, and then discharged into strands, cooled in water at a temperature of 25°C, and cut immediately to prepare master batch particles containing 10% by weight of silicon oxide particles.

(Reference Example 3-3)

A co-rotating type vented twin-shaft kneading extruder (manufactured by Nippon Steel, screw diameter 30 mm, screw length / screw Diameter=45.5) was heated to 265°C, 94.0 parts by mass of the polyester obtained in Reference Example 1-1 was supplied from the main feed port, and the surface-treated silicon oxide particles obtained in Reference Example 2-2 were supplied from the side feed port 2.0 parts by mass, and 4.0 parts by mass of multi-layer carbon nanotubes with an average fiber diameter of 0.06 μm and an average fiber length of 10 μm, melted and kneaded, spit out into strands, cooled in water at a temperature of 25 ° C, and immediately cut to make A master batch particle containing 2.0% by weight of silicon oxide particles and 4.0% by weight of multilayer carbon nanotubes was prepared.

(Reference Example 3-4)

A co-rotating type vented twin-shaft kneading extruder (manufactured by Nippon Steel, screw diameter 30 mm, screw length / screw Diameter=45.5) was heated to 265°C, 70.0 parts by mass of the polyester obtained in Reference Example 1-1 was supplied from the main feed port, and the surface-treated silicon oxide particles obtained in Reference Example 2-2 were supplied from the side feed port 2.0 parts by mass, and 28.0 parts by mass of the wollastonite particles obtained in Reference Example 2-3 were melted and kneaded, spit out into strands, cooled in water at a temperature of 25°C, and then cut immediately to make 2.0 wt % of the wollastonite particles. Masterbatch particles of silica particles, 28.0 wt% wollastonite particles.

(Reference Example 3-5)

The PPS powders and granules obtained in Reference Example 1-2 were melt-kneaded and extruded into strands in a uniaxial extruder set at 320° C., cut with a cutter, and pelletized.

(Reference Example 3-6)

A co-rotating type vented twin-shaft kneading extruder (manufactured by Nippon Steel, screw diameter 30 mm, screw length / screw Diameter=45.5) was heated to 310°C, 60 parts by mass of the PPS resin obtained in Reference Example 1-2 was supplied from the main feed port, and the surface-treated wollastonite obtained in Reference Example 2-1 was supplied from the side feed port 40 parts by mass of particles were melted and kneaded, and then discharged into strands, cooled in water at a temperature of 25° C., and then cut immediately to prepare master batch particles containing 40% by weight of wollastonite particles.

(Example 1)

67.5 parts by mass of the master batch pellet obtained in Reference Example 3-1 and 32.5 parts by mass of the polyester obtained in Reference Example 1-1 were mixed with vacuum drying at a temperature of 180° C. for 3 hours and then supplied to an extruder, It was melted at a temperature of 280° C. in a nitrogen atmosphere, and introduced into a T-die nozzle. Next, it was extruded from a T-die nozzle into a sheet as a molten monolayer sheet, and the molten monolayer sheet was adhered to a roller whose surface temperature was kept at 25°C by electrostatic application, and was cooled and solidified to obtain an unstretched monolayer. film.

Next, the unstretched single-layer film was preheated with a roll group heated to a temperature of 90° C., and then stretched 2.5 times in the longitudinal direction (longitudinal direction) using a heating roll with a temperature of 100° C., and a roll group with a temperature of 25° C. was used. After cooling, a uniaxially stretched film was obtained. Both ends of the obtained uniaxially stretched film were held by clips, while being introduced into a preheating zone at a temperature of 90°C in a tenter frame, and then continuously in a heating zone at a temperature of 100°C in the longitudinal direction in the right-angle direction (width). direction) extends 2.75 times. Further, heat treatment was performed at a temperature of 220°C for 20 seconds in a heat treatment zone 1 in the tenter frame, a heat treatment at a temperature of 150°C was further performed in a heat treatment zone 2 , and a heat treatment was performed at a temperature of 100°C in a heat treatment zone 3 . In addition, during the heat treatment, a relaxation treatment of 4% in the width direction is performed between the heat treatment zone 1 and the heat treatment zone 2. Next, it was uniformly cooled slowly and then wound up to obtain a biaxially stretched film with a thickness of 50 μm. The physical properties and characteristics of the obtained films are shown in Table 1.

(Example 2)

In Example 1, except that the amount of the master batch pellets supplied to the extruder was changed to 40.0 parts by mass and the amount of polyester was changed to 60.0 parts by mass, respectively, it was carried out in the same manner as in Example 1 to obtain a pellet with a thickness of 50 μm. biaxial extension stretch film. The physical properties and characteristics of the obtained films are shown in Table 1.

(Example 3)

In Example 1, except that the amount of the master batch pellets supplied to the extruder was changed to 30.0 parts by mass and the amount of polyester was changed to 70.0 parts by mass, respectively, it was carried out in the same manner as in Example 1 to obtain a pellet with a thickness of 50 μm. Biaxially stretched film. The physical properties and characteristics of the obtained films are shown in Table 1.

(Comparative Example 3)

In Example 1, except that the amount of the master batch pellets supplied to the extruder was changed to 20.0 parts by mass and the amount of polyester was changed to 80.0 parts by mass, respectively, it was carried out in the same manner as in Example 1 to obtain a pellet with a thickness of 50 μm. Biaxially stretched film. The physical properties and characteristics of the obtained films are shown in Table 1.

(Example 4)

In Reference Example 2-1, wollastonite particles with an average particle size of 4 μm and an aspect ratio of 8 (manufactured by Kinsei Matec Co., Ltd., SH-1800) were used instead of the wollastonite particles with an average particle size of 17 μm and an aspect ratio of 4. Other than that, it carried out similarly to Example 1, and obtained the biaxially stretched film of thickness 50 micrometers. The physical properties and characteristics of the obtained films are shown in Table 1.

(Comparative Example 1)

After mixing 10.0 parts by mass of the master batch pellets obtained in Reference Example 3-2 and 90.0 parts by mass of the polyester obtained in Reference Example 1-1, vacuum-drying at a temperature of 180° C. for 3 hours was supplied to an extruder, It was melted at a temperature of 280° C. in a nitrogen atmosphere, and introduced into a T-die nozzle. Next, it was extruded from a T-die nozzle into a sheet as a molten monolayer sheet, and the molten monolayer sheet was adhered to a roller whose surface temperature was kept at 25°C by electrostatic application, and was cooled and solidified to obtain an unstretched monolayer. film. Thereafter, it was carried out in the same manner as in Example 1 Stretching was performed by the operation to obtain a biaxially stretched film with a thickness of 50 μm. The physical properties and characteristics of the obtained films are shown in Table 1.

(Comparative Example 7)

50.0 parts by mass of the master batch pellets obtained in Reference Example 3-3 and 50.0 parts by mass of the polyester obtained in Reference Example 1-1 were mixed with vacuum-drying at a temperature of 180° C. for 3 hours and then supplied to an extruder, It was melted at a temperature of 280° C. in a nitrogen atmosphere, and introduced into a T-die nozzle. Next, it was extruded from a T-die nozzle into a sheet as a molten monolayer sheet, and the molten monolayer sheet was adhered to a roller whose surface temperature was kept at 25°C by electrostatic application, and was cooled and solidified to obtain an unstretched monolayer. film. Thereafter, it was stretched in the same manner as in Example 1 to obtain a biaxially stretched film with a thickness of 50 μm. The physical properties and characteristics of the obtained films are shown in Table 1.

(Example 6)

50.0 parts by mass of the master batch pellets obtained in Reference Example 3-4 and 50.0 parts by mass of the polyester obtained in Reference Example 1-1 were mixed with vacuum-drying at a temperature of 180° C. for 3 hours and then supplied to an extruder, It was melted at a temperature of 280° C. in a nitrogen atmosphere, and introduced into a T-die nozzle. Next, it was extruded from a T-die nozzle into a sheet as a molten monolayer sheet, and the molten monolayer sheet was adhered to a roller whose surface temperature was kept at 25°C by electrostatic application, and was cooled and solidified to obtain an unstretched monolayer. film. Thereafter, it was stretched in the same manner as in Example 1 to obtain a biaxially stretched film with a thickness of 50 μm. The physical properties and characteristics of the obtained films are shown in Table 1.

(Comparative Example 2)

In Comparative Example 1, except that the amount of the master batch pellets supplied to the extruder was changed to 60.0 parts by mass and the amount of polyester was changed to 40.0 parts by mass, respectively, In the same manner as in Comparative Example 1, a biaxially stretched film with a thickness of 50 μm was obtained. The physical properties and characteristics of the obtained films are shown in Table 1.

(Comparative Example 4)

In Example 2, a biaxially stretched film with a thickness of 50 μm was obtained in the same manner as in Example 2, except that the stretching ratio in the longitudinal direction was changed to 3.6 times and the stretching ratio in the width direction was changed to 3.6 times, respectively. The physical properties and characteristics of the obtained films are shown in Table 1.

(Comparative Example 6)

In Example 1, when obtaining an unstretched monolayer film, except that the thickness was adjusted to 50 μm and the subsequent steps were not performed, the same procedure as in Example 1 was carried out to obtain an unstretched monolayer film with a thickness of 50 μm. The physical properties and characteristics of the obtained films are shown in Table 1.

(Example 5)

The biaxially stretched film with a thickness of 50 μm obtained in Comparative Example 1 and the following mold 1 were heated to 200° C., the sheet was brought into contact with the uneven surface of the mold, and pressed at 20 MPa, and maintained in this state for 2 minutes. Then, after cooling the mold, the pressure was released, and the mold was released from the mold to obtain a film having surface irregularities. The physical properties and characteristics of the obtained films are shown in Table 1.

‧Mold 1

Material: Nickel, Pattern: Dot,

The pitch of the convex portion: 140 μm, the width of the convex portion: 70 μm, and the height of the convex portion: 10 μm.

(Comparative Example 5)

The biaxially stretched film with a thickness of 50 μm obtained in Comparative Example 1 and the following mold 2 were heated to 200° C., the sheet was brought into contact with the uneven surface of the mold, and the 20 MPa of pressure was applied, and this state was maintained for 2 minutes. Then, after cooling the mold, the pressure was released, and the mold was released from the mold to obtain a film having surface irregularities. The physical properties and characteristics of the obtained films are shown in Table 1.

‧Mold 2

Material: Nickel, Pattern: Dot,

Protrusion pitch: 500 μm, protrusion width: 380 μm, protrusion height: 100 μm.

(Example 7)

In Example 1, a biaxially stretched film having a thickness of 250 μm was obtained in the same manner as in Example 1, except that the extrusion output of the extruder was adjusted so that the film thickness after biaxial stretching was 250 μm. The physical properties and characteristics of the obtained films are shown in Table 1.

(Example 8)

Two extruders (extruder A and extruder B) were prepared, and 67.5 parts by mass of the master batch pellet obtained in Reference Example 3-1 and 32.5 parts by mass of polyester obtained in Reference Example 1-1 were mixed, After vacuum drying at a temperature of 180°C for 3 hours, it was supplied to extruder A, and only the polyester obtained in Reference Example 1-1 was vacuum-dried at a temperature of 180°C for 3 hours and supplied to extruder B. After the supplied resin was melted at a temperature of 280°C through each extruder in a nitrogen atmosphere, the resin of extruder B was laminated on both surfaces of the resin of extruder A into three layers, and was introduced into a T-die nozzle. At this time, the three layers were laminated so that the ratio of the lamination thicknesses of the three layers was 1:10:1. Next, a sheet was extruded from a T-die nozzle to form a molten laminated sheet, and the molten laminated sheet was adhered to a roller whose surface temperature was maintained at 25°C by electrostatic application, and was cooled and solidified to obtain an unstretched laminated film. After that, the extension was carried out in the same manner as in Example 1. , a biaxially stretched film with a thickness of 50 μm was obtained. The physical properties and characteristics of the obtained thin films are shown in Table 1.

(Example 9)

In Example 8, except that the amount of the master batch pellets supplied to the extruder A was changed to 40.0 parts by mass and the amount of polyester was changed to 60.0 parts by mass, it was carried out in the same manner as in Example 8 to obtain a thickness of 50 μm. The biaxially stretched film. The physical properties and characteristics of the obtained films are shown in Table 1.

(Example 10)

In Example 8, except that the amount of the master batch pellets supplied to the extruder A was changed to 30.0 parts by mass and the amount of polyester was changed to 70.0 parts by mass, it was carried out in the same manner as in Example 8 to obtain a thickness of 50 μm. The biaxially stretched film. The physical properties and characteristics of the obtained films are shown in Table 1.

(Comparative Example 9)

In Example 8, except having changed the amount of the master batch pellets supplied to the extruder A to 20.0 parts by mass and the amount of polyester to 80.0 parts by mass, respectively, it was carried out in the same manner as in Example 1 to obtain a thickness of 50 μm. The biaxially stretched film. The physical properties and characteristics of the obtained films are shown in Table 1.

(Example 11)

In Reference Example 2-1, wollastonite particles with an average particle size of 4 μm and an aspect ratio of 8 (manufactured by Kinsei Matec Co., Ltd., SH-1800) were used instead of the wollastonite particles with an average particle size of 17 μm and an aspect ratio of 4. Other than that, it carried out similarly to Example 8, and obtained the biaxially stretched film of thickness 50 micrometers. The physical properties and characteristics of the obtained films are shown in Table 1.

(Example 18)

In Reference Example 2-1, except for the use of metal silicon particles with an average particle size of 14 μm (Kinsei Matec Co., Ltd., M-Si# 350) was used in the same manner as in Example 8, except that the wollastonite particles having an average particle diameter of 17 μm and an aspect ratio of 4 were replaced, to obtain a biaxially stretched film with a thickness of 50 μm. The physical properties and characteristics of the obtained films are shown in Table 1.

(Example 19)

In Reference Example 2-1, except that aluminosilicate particles with an average particle size of 16 μm (Silatherm T 1360-0112, manufactured by Quarzwerke Co., Ltd.) were used instead of the wollastonite particles with an average particle size of 17 μm and an aspect ratio of 4, the same procedures were carried out. Example 8 was carried out in the same manner to obtain a biaxially stretched film with a thickness of 50 μm. The physical properties and characteristics of the obtained films are shown in Table 1.

(Example 12)

After mixing 50.0 parts by mass of the master batch pellets obtained in Reference Example 3-4 and 50.0 parts by mass of the polyester obtained in Reference Example 1-1, the mixture was vacuum-dried at a temperature of 180° C. for 3 hours, and then supplied to the extruder A. , except that it was melted at a temperature of 280° C. in a nitrogen atmosphere, it was carried out in the same manner as in Example 8 to obtain a biaxially stretched film with a thickness of 50 μm. The physical properties and characteristics of the obtained films are shown in Table 1.

(Comparative Example 10)

In Example 8, it was the same as Example 8 except that 10.0 parts by mass of the master batch pellet obtained in Reference Example 3-2 and 90.0 parts by mass of the polyester obtained in Reference Example 1-1 were mixed and supplied to the extruder A. This operation was carried out to obtain a biaxially stretched film with a thickness of 50 μm. The physical properties and characteristics of the obtained films are shown in Table 1.

(Example 13)

In Example 8, except that the film thickness after biaxial stretching became Except having adjusted the extrusion discharge amount of the extruder so that it might become 250 micrometers, it carried out similarly to Example 8, and obtained the biaxially stretched film of thickness 250 micrometers. The physical properties and characteristics of the obtained films are shown in Table 1.

(Example 14)

A biaxially stretched film with a thickness of 50 μm was obtained in the same manner as in Example 8, except that the ratio of the laminate thicknesses of the three layers was changed to 1:16:1. The physical properties and characteristics of the obtained films are shown in Table 1.

(Example 15)

A biaxially stretched film having a thickness of 50 μm was obtained in the same manner as in Example 8, except that the ratio of the laminate thicknesses of the three layers was changed to 1:8:1. The physical properties and characteristics of the obtained films are shown in Table 1.

(Example 16)

A biaxially stretched film having a thickness of 50 μm was obtained in the same manner as in Example 8, except that the ratio of the laminate thicknesses of the three layers was changed to 1:6:1. The physical properties and characteristics of the obtained films are shown in Table 1.

(Comparative Example 8)

A biaxially stretched film having a thickness of 50 μm was obtained in the same manner as in Example 8, except that the ratio of the laminate thicknesses of the three layers was changed to 1:4:1. The physical properties and characteristics of the obtained films are shown in Table 1.

(Comparative Example 11)

In Example 9, a biaxially stretched film with a thickness of 50 μm was obtained in the same manner as in Example 9, except that the stretching ratio in the longitudinal direction was changed to 3.6 times and the stretching ratio in the width direction was changed to 3.6 times, respectively. The physical properties and characteristics of the obtained films are shown in Table 1.

(Example 17)

Two extruders (extruder A and extruder B) were prepared, and 67.5 parts by mass of the master batch pellets obtained in Reference Example 3-6 and 32.5 parts by mass of the pellets obtained in Reference Example 3-5 were mixed in After vacuum drying at a temperature of 180°C for 3 hours, it was supplied to extruder A, and only the pellets obtained in Reference Example 3-5 were vacuum dried at a temperature of 180°C for 3 hours and supplied to extruder B. After the supplied resin was melted at a temperature of 320° C. through each extruder in a nitrogen atmosphere, the resin of extruder B was laminated on both surfaces of the resin of extruder A to form three layers and introduced into a T-die nozzle. At this time, the three layers were laminated so that the ratio of the lamination thicknesses of the three layers was 1:10:1. Next, a sheet was extruded from a T-die nozzle to form a molten laminated sheet, and the molten laminated sheet was adhered to a roller whose surface temperature was maintained at 25°C by electrostatic application, and was cooled and solidified to obtain an unstretched laminated film.

Next, the unstretched single-layer film was preheated with a roll group heated to a temperature of 100° C., and then stretched 2.5 times in the longitudinal direction (longitudinal direction) using a heating roll with a temperature of 110° C., and a roll group with a temperature of 25° C. was used. After cooling, a uniaxially stretched film was obtained. Both ends of the obtained uniaxially stretched film were held with clips, while being introduced into a preheating zone at a temperature of 100°C in a tenter frame, and then continuously in the preheating zone at a temperature of 110°C in the longitudinal direction in the right-angle direction ( Width direction) extends 2.75 times. Furthermore, heat treatment was performed at a temperature of 180° C. in the heat treatment zone 1 in the tenter, further heat treatment at a temperature of 230° C. in the heat treatment zone 2 , and heat treatment at a temperature of 130° C. in the heat treatment zone 3 . In addition, during the heat treatment, a relaxation treatment of 4% in the width direction is performed between the heat treatment zone 1 and the heat treatment zone 2. Next, it was uniformly cooled slowly and then wound up to obtain a biaxially stretched film with a thickness of 50 μm. The physical properties and characteristics of the obtained thin films are shown in Table 1.

[Industrial Availability]

According to the present invention, it is possible to provide a thin film having excellent electrical insulating properties, heat dissipation properties, and processability as compared with conventional thin films. The film can be applied to copper clad laminates, back sheets for solar cells, adhesive tapes, flexible printed circuit boards, membrane switches, planar heating elements, flat cables, insulating materials for rotating machines, insulating materials for batteries, etc. Emphasis on the use of electrical insulation and heat dissipation. In addition, it can also be used in adhesive tapes, release films, transfer films, design sheets, building materials, etc. by taking advantage of the surface properties of the film.

Claims (10)

A thin film, the number of coarse protrusions SPc (4000) on the surface of at least one side is 15 pieces/mm ² or more, the thickness of the thin film is 3 μm or more and 500 μm or less, and the thin film has a layer (P1 layer) containing inorganic particles, when Va/Vf1 is 1 or less when the content of the inorganic particles in the P1 layer is Vf1 (volume %) and the porosity in the P1 layer is Va (volume %). When the thin film Paragraph 1 request, wherein the P1 layer cross section in a manner perpendicular to the film plane direction and parallel to the film longitudinal direction is cut out of, when the number of the inorganic particles present of each 10000μm ² to Nf of (a), Nf of /Vf1 is 25 or less. The film of claim 1 or 2, wherein in the cross section of the P1 layer taken perpendicular to the film surface direction and parallel to the film length direction, the average equivalent circle diameter of the inorganic particles is 3 μm or more. The thin film of claim 1 or 2, wherein the thin film has a layer (P1 layer) containing inorganic particles, the thickness of the thin film is set as T (μm) and the number of coarse protrusions SPc (4000) is 15 pieces/mm ² or more of the surface For example, when the content of inorganic particles in the range from the surface to the thickness of 0.1T is set as Vfa (volume %), and the content of inorganic particles in the range from the thickness of 0.1T to the thickness of 0.9T is set as Vfb (volume %) ), Vfa/Vfb satisfies 0≦Vfa/Vfb<1. The film of claim 1 or 2, wherein the thermal conductivity in the thickness direction of the film is 0.15 W/mK or more, and the surface specific resistance is 10 ¹³ Ω/□ or more. The film of claim 1 or 2, wherein the film is mainly composed of polyester resin. The thin film according to claim 1 or 2, wherein the surface roughness Ra of the surface of which the number of coarse protrusions SPc(4000) is 15 pieces/mm ² or more is 100 nm or more. An electrical insulating sheet, which is formed using the thin film according to any one of claims 1 to 7. An adhesive tape, which is formed using the film according to any one of claims 1 to 7. A rotating machine is made by using the electrical insulating sheet as claimed in item 8.

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